For example, as a means of detecting deformation and load distribution, a flexible sensor using an elastomer has been developed. An actuator using an elastomer is highly flexible and can be easily made lightweight and compact, and thus its use in various fields, such as artificial muscle, medical equipment, fluid control, and the like, has been studied. For example, an actuator can be configured by arranging electrodes on both sides in a thickness direction of a dielectric film made of an elastomer. In an actuator of this kind, the dielectric film extends and contracts according to the magnitude of an applied voltage. Therefore, it is required that an electrode be extendable and contractible according to the deformation of the dielectric film so as to avoid interfering with the extension and contraction of the dielectric film. In addition, it is also required that a change in electrical resistance be small when the electrode is extended.
From such a point of view, for example, according to Patent Document 1, an electrode is formed from a paste in which an oil and an elastomer are mixed with a conductive agent such as carbon black and the like. As a conductive material capable of being formed into a thin film, Patent Document 2 discloses a paste in which flake-like silver particles and spherical silver particles are dispersed in a synthetic resin and an organic solvent. Patent Document 3 discloses a paste in which copper particles, a thermoplastic acrylic resin, a titanate coupling agent and an organic solvent are mixed. Patent Document 4 discloses a paste in which at least one kind of a binder selected from a synthetic rubber, a silicone resin and a thermoplastic polyester resin, and two kinds of scale-like silver powders having different average particle sizes, are mixed.